Is it possible to use the synchronized keyword directly to protect a single variable?

In Swift (iOS), the keyword synchronized is absent; it exists in Java. Therefore, you cannot directly use synchronized to protect a specific variable.

To protect access to a variable in Swift, other synchronization mechanisms are usually used, such as:

• Using DispatchQueue with barriers or serial queues.
• Using NSLock or other locking objects.

Example of protecting a variable using DispatchQueue:

class ThreadSafeCounter {
    private var value = 0
    private let queue = DispatchQueue(label: "com.example.counter")

    func increment() {
        queue.sync {
            value += 1
        }
    }

    func getValue() -> Int {
        return queue.sync { value }
    }
}

Thus, in iOS, to protect variables, you should use appropriate synchronization mechanisms rather than the synchronized keyword.